selftests/bpf: test cases for pkt/null checks in subprogs

The first test case, for pointer null checks, is equivalent to the
following pseudo-code.  It checks that the verifier does not complain on
line 6 and recognizes that ptr isn't null.

1: ptr = bpf_map_lookup_elem(map, &key);
2: ret = subprog(ptr) {
3:   return ptr != NULL;
4: }
5: if (ret)
6:   value = *ptr;

The second test case, for packet bound checks, is equivalent to the
following pseudo-code.  It checks that the verifier does not complain on
line 7 and recognizes that the packet is at least 1 byte long.

1: pkt_end = ctx.pkt_end;
2: ptr = ctx.pkt + 8;
3: ret = subprog(ptr, pkt_end) {
4:   return ptr <= pkt_end;
5: }
6: if (ret)
7:   value = *(u8 *)ctx.pkt;

Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c
index fb11240..9093a8f 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/calls.c
+++ b/tools/testing/selftests/bpf/verifier/calls.c
@@ -374,6 +374,31 @@
        .prog_type = BPF_PROG_TYPE_XDP,
        .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
 },
+{
+       "calls: ptr null check in subprog",
+       .insns = {
+       BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+       BPF_LD_MAP_FD(BPF_REG_1, 0),
+       BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+       BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
+       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+       BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_6, 0),
+       BPF_EXIT_INSN(),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
+       BPF_MOV64_IMM(BPF_REG_0, 1),
+       BPF_EXIT_INSN(),
+       },
+       .errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+       .fixup_map_hash_48b = { 3 },
+       .result_unpriv = REJECT,
+       .result = ACCEPT,
+       .retval = 0,
+},
 {
        "calls: two calls with args",
        .insns = {

diff --git a/tools/testing/selftests/bpf/verifier/direct_packet_access.c b/tools/testing/selftests/bpf/verifier/direct_packet_access.c
index e3fc22e..d5c596f 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/direct_packet_access.c
+++ b/tools/testing/selftests/bpf/verifier/direct_packet_access.c
@@ -631,3 +631,25 @@
        .errstr = "invalid access to packet",
        .prog_type = BPF_PROG_TYPE_SCHED_CLS,
 },
+{
+       "direct packet access: test29 (reg > pkt_end in subprog)",
+       .insns = {
+       BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
+                   offsetof(struct __sk_buff, data)),
+       BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+                   offsetof(struct __sk_buff, data_end)),
+       BPF_MOV64_REG(BPF_REG_3, BPF_REG_6),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 8),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
+       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+       BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_6, 0),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 1),
+       BPF_MOV64_IMM(BPF_REG_0, 1),
+       BPF_EXIT_INSN(),
+       },
+       .result = ACCEPT,
+       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},